Guide rails are used in elevator systems in order for elevator cars to be guided along an elevator shaft. The elevator shafts herein traditionally extend vertically in a building. However, horizontal shafts have also already been proposed in some instances. By virtue of the great lengths of shafts, the guide rails during fitting are typically assembled from individual rail elements.
In the fitting of the rail elements in vertical elevator shafts it has become accepted practice for the rail elements to be stacked on top of one another and for said rail elements to be fixed to the shaft wall only in the horizontal direction. This has the advantage that the rail elements along the vertical travel direction abut one another, this simultaneously enabling an expansion of the guide rail in the vertical direction in the case of temperature variations. The assembled guide rail thus behaves like a continuous guide rail.
A new type of elevator system such as is described in WO 2012/045606, for example, uses a linear motor for driving the elevator cars within the elevator shaft. A primary part of the linear motor herein is attached to the rail elements, and a secondary part of the linear motor is attached to the elevator car to be moved. This type of drive enables a plurality of elevator cars to be displaced simultaneously and in a mutually independent manner in the same shaft.
However, there are significant technical issues pertaining to the guide rails that are derived from the above. On the one hand, guide rails are to be equipped with the primary part of the linear motor. This additional weight has to be received by guide rails. On the other hand, there are no cables present in the case of this type of elevator, such that also all vertical forces (weight of the car, driving force of the car, braking forces) that act on the car have to be received by the guide rails. Moreover, since a multiplicity of cars operate in the same shaft, the proportion of said forces is also multiplied.
By virtue of this increased stress the concept of the stacked rail elements is no longer practically implementable since the lowermost rail elements can no longer absorb the load of the rail elements lying thereabove. Consequently, the rail elements must be individually connected to the shaft wall.
However, the drive concept of the linear motor leads to yet a further issue. As is also the case with other electric motors, the primary part inter alia heats up during operation. Since the primary part is attached to the rail elements, the heat is dissipated to the rail elements, on account of which a significantly higher thermal expansion results. In order for the latter to be taken into account, adjacent rail elements must have a mutual spacing (a so-called expansion joint).
Furthermore, subsidence also arises in the case of newly constructed buildings. Therefore, rail elements that are attached to the wall must have a mutual spacing that compensates for said subsidence. The gap width between the adjacent rail elements is reduced by the subsidence.
However, the individual components of the car slide along the guide rail in the operation of the elevator system. For example, one elevator car typically has a plurality of guide rollers which roll along a running track of the guide rail. Moreover, a shoe brake by way of which the elevator car is braked in that one or a plurality of brake shoes of the elevator car act(s) on the guide rail can be provided. As soon as components of this type switch between two adjacent rail elements, vibrations and noise are created by virtue of the spacing.
Thus a need exists to reduce these types of vibrations and noise.